Nowadays, various artificial fish beds of this kind are known, such as one having an arc-shaped section as shown in Japanese Utility Model Application Publication No. 55-88667 and another formed by assembling a plurality of ladder-shaped elements as shown in JUAP No. 56-35265.
According to the prior art mentioned above, these conventional artificial fish beds or fish-settling installations have fixing members or foundations which are formed by heaping stones on the sea floor. The stone-heaping operation for forming the foundation of the artificial fish bed is a very troublesome and labor intensive operation. In addition, the fixing member cannot expand, but only extends horizontally along the sea floor or merely increases in the area of its bottom face which contacts the sea floor. This, of course, is disadvantageous.
It has been proposed to develop an improved artificial fish bed which is easily constructed and installed, capable of enduring strong tidal currents and waves, and able to expand in upwards and downwards directions.